I'm having the same problem. PhantomJS/CasperJS works when the app is built with "sencha app build production" but it doesn't work in "development" mode. For some reason in development mode it never gets past the loading indicator.

I'm not sure what's the difference between the two but it's a real PITA.

I got around it by looking at the development.js microloader and more or less manually doing what it does. The key was to add the sencha-touch-all-debug.js script to my index.html. Now I keep an index-debug.html for testing and an index.html for building.